1. Field of the Invention
The present invention relates to a solder material test apparatus which tests a solder material used on a production line in a factory, a method of controlling the same, a solder material test program, and computer-readable recording medium storing the solder material test program.
2. Description of the Related Art
On the production line of printed boards, electronic components are mounted on the board by performing a printing process of printing a solder material on a board, a mounting process of mounting an electronic component on the printed solder material and a reflow process of fixing the electronic component on the board by soldering.
In the above-mentioned printing process, the solder material is put on the surface of a metal mask placed on the board. The metal mask is formed with an opening corresponding to a wiring pattern. The solder material on the metal mask surface is pushed and rotationally moved by a movable squeegee. Furthermore, the solder material being rotationally moved is squeezed out of the opening onto the board by the pressing force of the movable squeegee. Due to this, the solder material is printed to the board (see paragraph [0011] in JP-A-5-99831).
The metal mask is in continuous use for a number of boards, in a state the same one of solder material is rested thereon. Accordingly, the solder material is rotationally moved by the movable squeegee repeatedly each time printing is performed. Although the solder material gradually deteriorates due to rotational movement, the deteriorated solder material is to constitute a factor causing defects on the printed board.
For this reason, deterioration degree of the solder material on the metal mask should be analyzed in-line so as to determine whether or not the deterioration degree of the solder material exceeds an application limit (value considered that durability of the solder material reaches a limit). If the deterioration degree of the solder material exceeds the application limit, it is important to replace the solder material lying on the metal mask. In addition, before supplying a solder material onto the metal mask, it is important to analyze the deterioration degree of the solder material to be supplied and check whether or not the deterioration degree exceeds the application limit before supplying the solder material.
Here, the solder material has a viscosity, oxidation degree, and reducing power that serve as indexes in evaluating the deterioration degree thereof. The reason of the viscosity, oxidation degree and reducing power is an index is because of the following.
It is known that, as solder material deteriorates, its viscosity increases to proceed to oxidation and lower the reducing power. Herein, it is also known that, when a solder material highly viscous is printed on the board, such defects as ‘breakages’ or ‘blurs’ are ready to occur on the board thus printed. Meanwhile, it is also known that, in case an oxidized solder material is printed to the board, such inferiorities as ‘solder balls’ or ‘solder unfused’ are ready to occur on the post-reflow board. Furthermore, it is also known that, the solder material lowered in reducing power is printed to a board, such inferiority as ‘wettability reduction’ readily occurs on the post-reflow board.
Namely, the viscosity, oxidation degree and reducing power of a solder material are correlated to the occurrence rate of printed board inferiorities. For this reason, the viscosity, oxidation degree and reducing power of a solder material serves as a significant index in evaluating the deterioration degree of a solder material. Accordingly, it is possible to analyze the deterioration degree of the solder material by measuring at least one of the viscosity, oxidation degree, and reducing power of a solder material.
Conventionally, there are various methods to analyze the deterioration degree of solder material, as exemplified in JP-A-5-99831 (date opened: Apr. 23, 1993), JP-B-8-20434 (date published: Mar. 4, 1996) and JP-A-10-82737 (date opened: Mar. 31, 1998).
JP-A-5-99831 discloses a method to measure the viscosity of a solder material depending upon a velocity of a solder material flowing on a squeegee surface. JP-B-8-20434 discloses a method of measuring the acid degree of a solder material (oxidation degree and reducing power of the solder material) by conducting a titration by use of a solder material sampled. JP-A-10-82737 discloses a technique of measuring the surface oxidation rate (oxidation degree and reducing power of the surface of the solder material) of a solder material according to the ultraviolet-ray photoelectron spectroscopy.
Therefore, it is possible to analyze the deterioration degree of the solder material by using the viscosity, oxidation degree, and reducing power of a solder material measured by using the above-mentioned methods as deterioration data which indicates the deterioration degree of the solder material.
However, in the above-mentioned methods according to JP-A-5-99831, JP-B-8-20434, and JP-A-10-82737, the deterioration degree data of the solder material used in the printing process should be frequently measured and checked whether or not the deterioration degree data of the solder material exceeds the application limit (desired value). If the deterioration degree data of the solder material exceeds the application limit, the solder material should be changed in a prompt manner thereby taking a lot of labor and time.
At the same time, if it is possible to estimate a print time or the number of printing processes required until the deterioration degree data of the solder material used in the printing process exceeds the application limit (desired value), the deterioration degree does not need to be frequently measured such that the labor and time of a user who controls a production can be reduced.